Persistent Organic Pollutants (POPs) pose a great threat to human health and the ecological environment. As one of the main sources of POPs, the industrial chemical polychlorinated biphenyls (PCBs) not only can remain in the environment for a long time and can migrate for a long distance, but also have fat solubility and bioaccumulation, which is very toxic to humans, animals and plants Side effects have aroused great concern of the international community. At present, the commonly used detection methods for PCBs are mainly: fluorescence spectroscopy, chromatographic analysis and gas chromatography isotope dilution time-of-flight mass spectrometry, etc. These methods not only require complex and expensive instruments and equipment, but also have a long detection period, which cannot meet people ’s There is an urgent need for rapid and trace detection of special pollutants with high toxicity and low concentration.
In recent years, the Meng Guowen group of the Institute of Solid Physics, Institute of Material Science, Chinese Academy of Sciences is committed to exploring new methods for testing PCBs with excellent properties of nanomaterials. Their goal is to construct new nanostructures by design and use them as detection devices. Sensitive work unit, realizing fast real-time online detection of POPs with high sensitivity, high selection, high reliability and good repeatability. Through the unremitting efforts of scientific researchers, some preliminary progress has been made. For example: Invented a new method and prototype device for rapid detection of two PCBs (PCB29 and PCB101) based on the surface photovoltage change of porous ZnO (Langmuir 26, 13703 (2010); patent application number .6); based on silver nano Crystal "surface enhanced Raman scattering (SERS) effect for rapid detection of PCB77 (J. Appl. Phys. 107, 044315 (2010); Patent Application No. 9).
Researchers have found in the research that because each nano-dendrite is an independent small "unit" within a certain range, "vacancies" will appear between "units" and "units", so if the SERS signal The sampling point happens to be in the "vacant" position, and the obtained Raman signal cannot reflect the actual situation. On the basis of previous research, under the guidance of Meng Guowen, a mentor of the Institute of Ion Beams and Bioengineering, Chinese Academy of Sciences, and Huang Qing, a PhD student, based on the surface of precious metal particles or sols with nano-level roughness Under the irradiation of laser, the SERS effect of the Raman scattering signal of the adsorbed molecule is greatly enhanced, a highly ordered Ag @ Au nanorod array with repeatable SERS signal in a large area is constructed, and the rapid detection of trace PCBs is realized . In order to check the repeatability and consistency of the SERS signal at different positions on the substrate, they randomly selected 7 points on the same substrate, and the measurement results found that the characteristic peak of R6G has a very small intensity fluctuation and very small, indicating that this new substrate SERS activity is uniform, stable, reliable and repeatable. They achieved rapid trace detection of PCB 20 on the substrate.
Relevant achievements applied for a national patent (200910184967.8), and the written paper was published in Adv. Mater. 22, 4136 (2010). This work was supported by major scientific research projects such as "Nano Research", the National Natural Science Foundation of China, and the Innovation Project of the Chinese Academy of Sciences.
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